Each of the following describes the pyruvate oxidation reaction except that _____________________.

• A. It connects glycolysis to the citric acid cycle.
• B. Each pyruvate is converted to an acetyl-CoA molecule.
• C. NAD⁺ is reduced to NADH.
• D. This reaction occurs within the cytoplasm.
• E. Carbon dioxide is released as a by-product.

Answer: (D)

Verified step by step guidance

1. Understand the context of pyruvate oxidation: Pyruvate oxidation is a crucial step in cellular respiration that links glycolysis to the citric acid cycle.
2. Identify the location of pyruvate oxidation: Pyruvate oxidation occurs in the mitochondria, specifically in the mitochondrial matrix, not in the cytoplasm.
3. Recognize the conversion process: During pyruvate oxidation, each pyruvate molecule is converted into an acetyl-CoA molecule, which is then used in the citric acid cycle.
4. Consider the role of electron carriers: NAD+ is reduced to NADH during pyruvate oxidation, which is important for the electron transport chain.
5. Note the release of by-products: Carbon dioxide is released as a by-product during pyruvate oxidation, which is a key step in the decarboxylation process.